Area Forecast Discussion
Issued by NWS Fairbanks, AK
Issued by NWS Fairbanks, AK
726 FXAK69 PAFG 211450 AFDAFG Northern Alaska Forecast Discussion National Weather Service Fairbanks AK 650 AM AKDT Fri Jun 21 2024 .SYNOPSIS... A thermal low pressure trough stretching from Eagle to Tanana to Point Hope will move to Chicken to Nenana to Point Hope by 4pm Fri, and to Northway to Denali to Point Hope by 4am Sat, and to Northway to McGrath to Anaktuvuk Pass to Point Hope by 4pm Sat and remain there into Sun. A second thermal trough from Tanana to McGrath will move to Nenana to McGrath by 4pm Fri, and then to Denali south by 4am Sat. The thermal troughs will serve as focus mechanisms for convection through Sat. Expect isolated to scattered showers along the troughs with isolated thunderstorms. Expect widely scattered thunderstorms in the afternoon/evening today along the Alaska Range and over the Western/Central Interior and over the Western Interior on Sat. Today is expected to be slightly warmer and drier in most areas, except the Southeast Interior and Southwest Interior which can expect scattered to numerous showers today into tonight. A drying and warming trend will occur across the Interior through the weekend. Next week hot and dry conditions are expected over the Interior. From Fairbanks northeast, northeast winds will blow at 10 mph this afternoon into Sat, and combined with temperatures in upper 70s and lowers 80s, and RH near 25%, will bring near Red Flag conditions to the Interior from Fairbanks northeast this afternoon and evening and Sat afternoon/evening. These winds will also push smoke southwest of the Richardson Highway this afternoon with smoke remaining southwest of the Richardson Highway through Sat night. High pressure north of the Arctic Coast is expected to push stratus clouds and fog along the coast today, with the stratus and fog remaining there through the weekend. High pressure building over the Chukchi Sea and Eastern Bering Sea through tonight is expected to cause stratus and fog to form over those areas today and tonight, and to push into the West Coast tonight and then remain along the West Coast through the weekend, although burning off along the coast during the PM each day. && .DISCUSSION... Models initialize well aloft at 00Z and show similar conditions aloft through Sun, with slight differences developing next week. Will use a blend of models for features aloft through the weekend. The strong ridge aloft stretching from NW Canada across Northern AK to the Chukchi Sea will build slightly through Sat, then weaken slightly on Sun as a strong low aloft over the Arctic Ocean approaches the North Slope. Heights aloft will build over the Interior next week leading to a return to hot and dry conditions over the Interior, while the coasts remain close to normal temperatures. A weak short wave trough over the YK Delta will remain stationary today, then drift east over the SW Interior tonight and Sat, then strengthen on Sun as more short wave energy feeds into it from the west. This will cause scattered showers and isolated thunderstorms today that will move over the Western Interior tonight and Sat, with isolated to scattered showers and isolated PM thunderstorms over the Western and Central Interior on Sun. A second weak short wave trough over the SE Interior will weaken slowly in place through Sat. This is causing scattered showers and isolated thunderstorms over the SE Interior that will increase to scattered to numerous showers and Isolated to widely scattered thunderstorms this PM, then taper off to isolated showers after midnight tonight, with scattered showers and isolated PM thunderstorms over the SE Interior on Sat, then few if any showers over the Eastern Interior on Sun. Could see another 0.25-0.50 inch of rain in the SE Interior through tonight. At 850 mb, temperatures warm 1-2C today compared to Thu, then warm another 1-2C over the weekend. This will cause today to be slightly warmer than Thu in most areas, with a warming and drying trend most areas over the weekend. At the surface at 06Z, models all verify 2-3 mb too weak on the High north of the Arctic Coast, 4-6mb too weak on the low over the Gulf of AK, and the NAM and GFS are 2-3 mb too strong on the thermal low over the Southern Yukon Territory while the ECMWF and Canadian models verify well on those features. With the stronger than forecast gradient across AK, expect slightly stronger winds than models indicate through Brooks Range Passes and along the West Coast through at least tonight. Will use a blend of models for surface features and winds through Sun, but boost up winds 3-5 kt above models through Brooks Range Passes and along the West Coast today through Sat. Expect north winds 15 mph gusting to 25 mph through Brooks Range passes through tonight, otherwise winds in the Interior should remain below 15 mph through Sun. Along the West Coast and Western Arctic Coast expect winds up to 20 mph but not greater through Sun. Coastal Hazard Potential Days 3 and 4...None. && .FIRE WEATHER... A thermal low pressure trough stretching from Eagle to Tanana to Point Hope will move to Chicken to Nenana to Point Hope by 4pm Fri, and to Northway to Denali to Point Hope by 4am Sat, and to Northway to McGrath to Anaktuvuk Pass to Point Hope by 4pm Sat and remain there into Sun. A second thermal trough from Tanana to McGrath will move to Nenana to McGrath by 4pm Fri, and then to Denali south by 4am Sat. The thermal troughs will serve as focus mechanisms for convection through Sat. Expect isolated to scattered showers along the troughs with isolated thunderstorms. Expect widely scattered thunderstorms in the afternoon/evening today along the Alaska Range and over the Western/Central Interior and over the Western Interior on Sat. Today is expected to be slightly warmer and drier in most areas, except the Southeast Interior and Southwest Interior which can expect wetting rains today into tonight. A drying and warming trend will occur across the Interior through the weekend. Next week hot and dry conditions are expected over the Interior. From Fairbanks northeast, northeast winds will blow at 10 mph this afternoon into Sat, and combined with temperatures in upper 70s and lowers 80s, and RH near 25%, will bring near Red Flag conditions to the Interior from Fairbanks northeast this afternoon and evening and Sat afternoon/evening. && .HYDROLOGY... Could see another 0.25-0.50 inch of rain the SE Interior through tonight, which is in additional to the 0.25-0.50 inch seen in that same area in the past 24hrs. This will lead to rises on creeks and rivers in the Alaska Range east of Denali and in the Upper Charlie and Upper Fortymile Rivers today and Sat. && .AFG WATCHES/WARNINGS/ADVISORIES... AK...Dense Smoke Advisory for AKZ839-840. PK...Small Craft Advisory for PKZ812. Small Craft Advisory for PKZ858. && $$ JB